From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754765AbZESHGz (ORCPT ); Tue, 19 May 2009 03:06:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753345AbZESHGr (ORCPT ); Tue, 19 May 2009 03:06:47 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:57967 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753033AbZESHGq (ORCPT ); Tue, 19 May 2009 03:06:46 -0400 Message-ID: <4A125ACA.5080107@cn.fujitsu.com> Date: Tue, 19 May 2009 15:07:54 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: raspl@linux.vnet.ibm.com CC: linux-btrace@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com Subject: Re: [Patch] blktrace: remove debugfs entries on bad path References: <4A115BA5.6090905@linux.vnet.ibm.com> <4A1207DE.4000409@cn.fujitsu.com> <4A1255E1.1060301@linux.vnet.ibm.com> In-Reply-To: <4A1255E1.1060301@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Stefan Raspl wrote: > Li Zefan wrote: >> A better title: >> [Patch] blktrace: remove debugfs entries on bad path >> >> Stefan Raspl wrote: >>> debugfs directory entries for devices are not removed on bad path. >> Can you be more elaborate on how to reproduce this issue? > > It can happen for most bad pathes within do_blk_trace_setup(). One Now I see what you meant by "bad path". :) I'd say "some failure pathes", but not "most". > way to trigger is to set the Vmalloc space via the respective kernel > parameter to a value that is so small that it will not suffice for > the 2MB per device and cpu that is required. For instance, set > vmalloc=10M and start blktrace on a system with 2 cpus on 7 devices. > Depending on how much Vmalloc space is still free, the final 2 or 3 > devices will fail with a message like this: > > BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error > Yes, this can happen under extreme memory stress. Thanks for the fix: Acked-by: Li Zefan Could you resend the patch to Ingo, with a better title and a better changelog (but IMHO we don't need to explain how to set up a memory stress to trigger this issue) and my ack tag? Now blktrace patches go to Ingo.